add kiss radio env to most of the variants

variants/heltec_ct62/platformio.ini

@@ -150,3 +150,8 @@ build_src_filter = ${Heltec_ct62.build_src_filter}
 lib_deps =
   ${Heltec_ct62.lib_deps}
   ${esp32_ota.lib_deps}
+
+[env:Heltec_ct62_kiss_modem]
+extends = Heltec_ct62
+build_src_filter = ${Heltec_ct62.build_src_filter}
+  +<../examples/kiss_modem/>